A variety of topical treatments are known in the art for mitigating dermatological conditions of the skin which frequently relate to the natural process of aging. Other factors, such as exposure to the sun or the resulting ultraviolet radiation therefrom, improper care and/or diet, stress, nutritional deficiencies, and genetic propensities also contribute to the development of adverse skin conditions, such as fine lines, wrinkles, especially of the facial skin, age spots, keratoses, dry skin, lack of skin tautness and suppleness, and depigmentation.
Many of the compositions described for topical treatment of the skin include components which have adverse side effects to the user, such as drying, burning, stinging, scaling and itching, irritation to the skin, and induction of photosensitivity. Indeed, methods and compositions commonly used for reducing fine lines and/or wrinkles contain acids, particularly, alpha (.alpha.)-hydroxy acids, such as glycolic acid, lactic acid, tartaric acid and citric acid, and salts thereof, or they contain tretinoin, also known as all-trans retinoic acid or retinol (Vitamin A), or ascorbic acid (Vitamin C), all of which can induce the above-mentioned disadvantageous effects, often due to a lowering of the pH of the skin, among other factors. With particular regard to topical compositions containing tretinoin, medical reports have documented a number of other adverse skin reactions typically associated with their use, namely, burning, tingling, stinging, dryness, peeling, erythema, itching, skin dermatitis, localized swelling and sun sensitivity.
Particular examples of compositions and methods containing retinol or retinoic acid for treating skin conditions and/or reducing wrinkles are found in U.S. Pat. No. 4,826,828 to J. M. Wilmott et al.; U.S. Pat. Nos. 4,603,146, 4,877,805 and 4,888,342 to A. M. Kligman. Particular examples of compositions and methods employing, among other ingredients, various percentages of one or more .alpha.-hydroxy acids for treating skin conditions and/or reducing wrinkles are found in U.S. Pat. No. 5,547,988 to R. J. Yu et al.; U.S. Pat. No. 5,422,370 to R. J. Yu et al.; U.S. Pat. No. 5,389,677 to R. J. Yu et al.; U.S. Pat. No. 5,407,958 to J. Heath et al.; U.S. Pat. Nos. 5,091,171, 5,093,360, 5,561,158, 5,561,157, 5,554,597 and 5,554,652 to E. J. Van Scott et al.; U.S. Pat. No. 5,441,740 to S. N. Ozlen and U.S. Pat. No. 5,407,958 to J. L. Heath et al.
Methods and compositions containing permeation enhancers for enhancing and/or controlling penetration of topically applied pharmacologically active agents are further known in the art. Specifically, U.S. Pat. No. 5,326,566 to P. V. Parab discloses the use of dibutyl adipate (DBA) and isopropyl myristate (IPM) to increase the skin permeation of an active or drug, for example, .alpha.-hydroxy acid, or a cosmetically acceptable salt form of .alpha.-hydroxy acid, and retinoids, after topical application. However, prior to the present invention, those skilled in the art would have had no reason or incentive to employ a permeation enhancer, much less DBA/IPM, in methods and formulations which contain less than effective amounts of the afore-mentioned active agents, or which are devoid of such agents, in the treatment of fine lines and/or wrinkles associated with intrinsic or extrinsic ageing.
U.S. Pat. No. 5,326,566 also discloses vehicle compositions that are similar, but not identical, to the compositions of the present invention. Those having skill in the art are taught from this patent that the disclosed compositions are useful only for the enhanced penetration into the skin of a pharmacologically active agent contained therein. The teachings of this patent do not allow those skilled in the art to learn or appreciate that a vehicle composition containing a less than effective amount of an active agent, or containing no active agent, would have any significant or beneficial effect to the user, particularly, for reducing fine lines and/or wrinkles in the skin.
In contrast to the present invention, pharmacologically active agents that are directed to the problem addressed by the present invention frequently include the use of skin proteins such as collagen and/or elastin, either singly or in combination (see, for example, U.S. Pat. Nos. 3,991,184; 4,179,333; 3,941,722; and German Pat. No. 2,804,024). Other compositions include steroids, such as pregnenolone, in combination with elastin (U.S. Pat. No. 4,474,763).
The present invention was discovered to afford surprising benefits and results in the reduction of fine lines and/or wrinkles, including fine wrinkles, by providing methods and compositions in the absence of, or containing noneffective amounts for such purpose, of the conventionally-used active components of anti-wrinkle compositions and methods, such as the .alpha.-hydroxy acids, retinoic acid and/or derivatives and salts thereof.